Eight years ago, Leanne Rowe was in a serious car crash that resulted in a broken back and jaw. But when the former bus driver and Australian Army Reserve member recovered, she was left with something completely unexpected: a French accent.

Rowe, who is now unable to speak with her original Aussie accent, said she has become a "recluse," and often has her daughter speak for her in public.

"I am not French," Rowe told the Australian Broadcasting Corporation (ABC) on Sunday. "It makes me so angry because I am Australian."

How can this occur?

Foreign accent syndrome is an extremely rare condition in which brain injuries change a person's speech patterns, giving them a different accent. The first known case was reported in 1941, when a Norwegian woman suffered shrapnel injuries to the brain during a German bombing run -- and started speaking with a German accent. Since then there have been only a few dozen reported cases.

"It's an impairment of motor control," said Dr. Karen Croot, one of the few experts in foreign accent syndrome. "Speech is one of the most complicated things we do, and there are a lot of brain centers involved in coordinating a lot of moving parts. If one or more of them are damaged, that can affect the timing, melody and tension of their speech.

"In a sense it's not a communication impairment -- a person can make themselves understood perfectly well."

But foreign accent syndrome can be psychologically difficult for sufferers.

"There can be a lack of understanding of how difficult it can be for the person with the acquired accent," said Croot. "There's sort of a response of, 'get rid of the accent, stop putting it on, go back.' If you think about your own accent, it's a part of your identity. Changing your accent projects a different identity."

In 2010, Sarah Colwill, a 35-year-old British woman, began speaking with what sounded like a Chinese accent after suffering a serious migraine.

"To think I am stuck with this Chinese accent is getting me down," she said. "My voice has started to annoy me now. It is not my voice."

Yet other patients don't mind as much.

"One of the ladies I worked with was an English speaker who started sounding Irish. She reported feeling positive about it. For her it was sort of an interesting new persona."

Other patients eventually see their speech return to normal. "I worked on a case of an Australian who was in a car accident, and consequently had an American accent. That accent went away about 5 months later," said Croot.

According to Croot, sufferers may try to regain their former accents by doing exercises. "They need to practice repositioning their mouth, just as they would practice a tennis serve. It's motor skill practice."

Treatments used for similar motor speech disorders, apraxia of speech and dysarthria, have also been deployed for patients of foreign accent syndrome in the last few years with "positive" results.

Rowe, however, has decided to stop trying to "hold in" her accent. "For me, it was not healthy," she said.

"It has affected her life greatly," her daughter explained. "People see the funny side of it, and think it's really interesting... but I've seen the impacts on mum's life."